publishivy="false" seems to stop publishing?

If I have

<target name="publish-local" depends="dist">
<ivy:publish resolver="local" artifactspattern="${build}/[artifact].[ext]"/>
</target>

Everything works fine:

publish-local:
[ivy:publish] :: delivering :: bt#pal;working@adrian-small-laptop :: 20110328142739 :: integration :: Mon Mar 28 14:27:39 BST 2011
[ivy:publish] delivering ivy file to /home/adrian/work/svn/smit-pal/trunk/pal/build/ivy.xml
[ivy:publish] :: publishing :: bt#pal
[ivy:publish] published pal to /home/adrian/.ivy2/local/bt/pal/20110328142739.part/wars/pal.war
[ivy:publish] published ivy to /home/adrian/.ivy2/local/bt/pal/20110328142739.part/ivys/ivy.xml
[ivy:publish] publish commited: moved /home/adrian/.ivy2/local/bt/pal/20110328142739.part
[ivy:publish] to /home/adrian/.ivy2/local/bt/pal/20110328142739

However, if I have

<target name="publish-local" depends="dist">
<ivy:publish resolver="local" artifactspattern="${build}/[artifact].[ext]" publishivy="false"/> </target>

I get:

publish-local:
[ivy:publish] :: publishing :: bt#pal
[ivy:publish] published pal to /home/adrian/.ivy2/local/bt/pal/20110328142819.part/wars/pal.war
[ivy:publish] publish aborted: nothing was started

BUILD FAILED
/home/adrian/work/svn/smit-pal/trunk/pal/build.xml:109: impossible to publish artifacts for bt#pal;working@adrian-small-laptop: java.io.IOException: publish transaction commit error for /home/adrian/.ivy2/local/bt/pal/working@adrian-small-laptop: rolled back

Is this something I'm doing wrong, or a bug?